Java Script Sentence Break Down

I want to break down a sentence like "Hello World!, Java Script is a best Scripting Language" into a each word I would have to convert the sentence into an array. Right?? And secondly if I want to break down those words in the array into letters then what do I have to do? Meaning I want "Hello World!" to be broke down into "H, e, l, l, o" & "w,o,r,l,d!".